I have a list of datetimes that are in an array and seem to be "out of order". Attached is a screenshot that shows them in their relative index values (0 through 6)

I need to extract the earliest and latest datetimes so that I can subtract them from one another and calculate the number of months between them. The LAST() value from the array does not always return the latest datetime value. How can I go about doing this?

The MAX() function works only on integer/double values.